Method for the gastight packaging of objects using a film material fitting tightly on the objects and a device for the gastight packaging of objects

ABSTRACT

In the case of a method for the gastight packaging of objects using a film material fitting tightly on the objects using a vacuum, the object being placed in a tray and a deep-drawable film being attached to the tray for sealing, it is provided that a tray having at least one peripheral rim is used to form the packaging, the deep-drawable film is cut to the size of the peripheral rim, and that the deep-drawable film is subsequently and/or simultaneously applied to the peripheral rim in a gastight manner. A device preferably for carrying out this method has at least one cutting device for the deep-drawable film.

The present invention relates to a method for the gastight packaging ofobjects using a film material fitting tightly on the objects using avacuum, the object being placed in a tray and a deep-drawable film beingattached to the tray for sealing.

The present invention also relates to a device for the gastightpackaging of objects using a film material fitting tightly on theobjects using a vacuum, preferably for carrying out the abovementionedmethod, including a supporting surface for at least one tray and atleast one sealing tool for the deep-drawable film. Finally, the presentinvention relates to a packaging.

The method and devices of the abovementioned species are used to packageobjects. These objects may be inorganic products, such as tools orstationery, which are kept for sale in corresponding packaging. Inparticular when a vacuum is used to deep-draw the film that isheat-sealed to the tray, the objects may be organic products, such asfoodstuffs. Meats and sausages in particular are packaged using thistype of packaging in order to ensure the smallest possible gas volume inthe interior space of the packaging.

In the known methods an object is placed in a tray and the deep-drawablefilm is then heat-sealed to the tray. After the deep-drawing operation,the film is cut to the size of the tray, which often includes cutting ofthe film and tray in one step, e.g., when the tray shifts. This maydisadvantageously result in sharp tray edges. A further disadvantage isthat this subsequent cutting is performed on film that is still heatedfor the heat-sealing process. The film in its heated state has a softconsistency so that it is only able to provide minimal resistance to acutting knife. This results in jagged edges causing unattractivecreasing and warping of the cut film edges.

The object of the present invention is to provide a method for packagingobjects in attractive gastight packaging. A device facilitating such apackaging method and a packaging are also to be provided.

With respect to the method, this object is achieved according to thepresent invention in that a tray having a peripheral rim is used to formthe packaging, the deep-drawable film is cut to the size of theperipheral rim, and in that the deep-drawable film is appliedsubsequently and/or simultaneously to the peripheral rim in a gastightmanner.

A tray having a peripheral rim is also used in the method according tothe present invention. However, this peripheral rim is not damagedduring the packaging of an object so that this rim may be provided inadvance with an attractive grippable edge or other design. According tothe present invention, the peripheral rim of the tray is protected inthat the deep-drawable film is cut to size prior to being applied to theperipheral rim.

Therefore the processing sequence in the method of the present inventionis the reverse of that of the related art. The film is first cut to sizeand then applied. This has the advantage that the film is cut in thecold state. In this state, the film is hardened so that smooth edges areable to be cut. The creation of ripples and warping is advantageouslyprevented. Cutting of the film after the heat-sealing operation, i.e.,in the heated state, is also prevented. The peripheral rims of the trayare also not cut since the film is cut in its cold state in a manner inwhich the cutting tools provided for this purpose do not come intocontact with the tray. A rim structure of the tray is thereforemaintained and sharp cut edges advantageously do not occur.

According to a first further refinement of the method of the presentinvention, the deep-drawable film is heat-sealed onto the peripheralrim. The heat-sealing creates a secure and gastight connection betweenthe film and the tray. The heat-sealing of the film previously cut tosize also heats the film so that it is suitable for a subsequent orsimultaneous deep-draw operation due to its heated state. Thedeep-drawable film is able to be expanded easily in this state.

To be able to perform the deep-drawing operation, a further refinementof the present invention provides for a vacuum to be positioned in thesurrounding region of the tray. The vacuum may be used to set pressureconditions so that deep-drawing of the film results in response to theformation of a pressure drop. The deep-drawing operation causes the filmto fit tightly on the object to be packaged as well as on areas of thetray not occupied by the object according to the skin method.

In a further refinement of the method according to the presentinvention, an overpressure may be formed in the surrounding region ofthe deep-drawable film on the side facing away from the tray. Theoverpressure formable on the side of the deep-drawable film facing awayfrom the tray may be applied to this side. This supports the vacuum onthe other side of the deep-drawable film in order to achieve thetightest possible fitting of the deep-drawable film on the object to bepackaged. This tight fit namely advantageously ensures not only that theobject is fixed in place but also, for example in the case of objectscontaining meat, that liquids in the meat are not able to escape.Therefore, a marinade or the meat's own juice is able to be contained inthe product so that the product does not dry out and stays fresh despitethe longer shelf life achieved by the packaging. The overpressure may begenerated quickly to achieve faster and tighter fitting of the film.

With respect to achieving the device objective, the present inventionprovides for the device to have a supporting surface for at least onetray, the sealing tool for the deep-drawable film, as well as at leastone cutting device for the deep-drawable film.

According to the method of the present invention, the film is first cutto size and then applied to the tray. Due to this procedure, a separatecutting station for the film is no longer necessary. According to thepresent invention, it may be assigned to the device since the film iscut in advance or at the same time as the sealing or heat-sealing of thefilm.

The cutting device preferably includes knife blades which are able tosuccessfully cut the deep-drawable film.

According to another further refinement of the device according to thepresent invention, the cutting device is spatially assigned to thesealing tool. This spatial assignment renders possible simultaneouscutting and sealing or cutting followed by sealing. Although the cuttingdevice and sealing tool are spatially assigned to one another, bothassemblies are structurally independent of one another so that thecutting and sealing work steps may be performed separately.

The cutting device is able to move around the sealing tool. If thesealing tool has a rectangular design, for example, the knife blades ofthe cutting device are able to move around this sealing tool like aframe. Prior to the sealing tool being applied to the film, the knifeblades configured in a frame-like manner cut the film to size.

With respect to the structural design of the device, a furtherrefinement of the present invention provides for the supporting surfacefor the tray and/or the sealing tool to be designed to beheight-adjustable. As a result, the supporting surface and the sealingtool are able to be moved together and moved apart. The moving togethermotion is used to apply the sealing tool to the deep-drawable film whenthe film is fitted to the peripheral rim of the tray.

According to another further refinement of the present invention, thesupporting surface has at least one supporting apparatus for theperipheral rim of the tray. The tray is able to be inserted into thesupporting apparatus for the peripheral rim via the supporting surface.The peripheral rim is preferably positioned on this supporting apparatusso that it is ready for the heat-sealing or sealing with thedeep-drawable film. The supporting apparatus supports the peripheral rimand forms a counter support for the sealing tool to be applied to therim.

According to another further refinement of the device of the presentinvention, a spacer plate which may be placed on the supportingapparatus for the peripheral rim is situated between the trays and thedeep-drawable film, the peripheral rim remaining at least sectionallyfree in this process. This spacer plate provided according to thepresent invention supports the advance cutting to size of thedeep-drawable film before it is heat-sealed or sealed onto theperipheral rim of the tray. This spacer plate may be placed for thispurpose on the peripheral rims of the tray accommodated in thesupporting apparatus. The top surface of the spacer plate now forms aplane situated above the peripheral rim. The deep-drawable film may beplaced on this plane and the cutting device may be applied to thedeep-drawable film on this plane. Once the deep-drawable film has beencut to size, it falls through the spacer plate onto the peripheral rims.These peripheral rims are not covered by the spacer plate. The otherregions of the tray may also remain free so that the sealing tool may beapplied to a large surface in order to heat-seal the deep-drawable filmwhile simultaneously heating it for a subsequent or simultaneousdeep-draw operation. At least one opening able to be positioned to havethe same coverage as the container is preferably situated in the spacerplate. This opening then has dimensions corresponding to those of thesealing tool.

When using this spacer plate with the openings, it is advantageous tospatially assign the cutting device to the sealing tool. When moving thesealing tool to the deep-drawable film, the cutting device may be movedin at the same time. The cutting device is preferably able to be movedpast an edge of the opening in the spacer plate at a close distance sothat a trimming effect results between a knife blade of the cuttingdevice and this edge of the opening, thereby cutting the still colddeep-drawable film while producing a clean cut edge. In this context,the cutting tool is preferably decoupled from the sealing tool andspring-suspended. This decoupling makes it possible for the sealing toolto be moved closer to the tray than the cutting tool. After this movingin of the sealing tool, sealing may be performed between the film andtray while the cutting tool remains in a position removed from the trayso that the peripheral rim of the tray is not damaged.

According to another embodiment of the device of the present invention,at least one overpressure line preferably runs through the sealing tool.The sealing tool is situated on the side of the deep-drawable filmfacing away from the tray. An overpressure medium, e.g. air, may besupplied via the overpressure line running through the sealing tool inorder to generate an overpressure preferably provided according to themethod on this side of the film.

Independent protection is also claimed for a packaging producedaccording to the method of the present invention. According to thepresent invention, this packaging is characterized in that afterplacement of the deep-drawable film on at least one peripheral rim ofthe tray, this rim is sectionally covered.

Therefore, according to the present invention, the film placed on theperipheral rim does not completely cover this rim. The film may have anoffset with respect to the outer edge of the peripheral rim so that itdoes not come into contact with this rim. It may be heat-sealed to aregion of the peripheral rim at a distance from the outer edge of theperipheral rim. This produces a clean seam.

In this context, a peripheral rim of the tray is always the region ofthe tray surface enclosing the periphery of at least one depression inthe tray. The tray may have a single depression surrounded by aperipheral rim. It is also possible for a plurality of depressions to besituated in one packaging, for example in the case of a plurality ofyogurt containers. A separate deep-drawable film may be assigned to eachof these depressions and attached only to the peripheral rim of theindividual depression. As a result, the various depressions are notcovered with one film but instead a plurality of films is provided. Thispackaging has regions not covered by film between the individualdepressions. Perforations may then preferably be introduced in theseregions to facilitate separation of the individual packaging regions. Inthis case pull-off tabs of the deep-drawable film may also moved from aposition in the outer region of the total packaging to an inner region,e.g. to where the deep-drawable films of a plurality of depressions areclose to one another.

An exemplary embodiment of the device of the present invention fromwhich other inventive features arise is displayed in the drawing. Thefigures show:

FIGS. 1 through 4 show sectional views of a device for the gastightpackaging of objects using a film material filting tightly on theobjects in various processing situations during a packaging operation;and

FIG. 5 shows an enlarged representation of detail V in FIG. 4.

The device in the figures has a lower tool 9 and an upper tool 1. Lowertool 9 includes two supporting tables 8 for two trays 6. Each of thetrays has a peripheral rim 10. Supporting tables 8 are set up on aheight-adjustable frame 11.

Two sealing tools 2 are accommodated in upper tool 1. Upper tool 1 isdesigned to be completely height-adjustable.

Cutting devices 3 which are configured as knives moving around sealingtools 2 are spatially assigned to sealing tools 2. Cutting devices 3 areaccommodated in spring-suspended knife holders 12.

FIG. 1 also shows a deep-drawable film 4. Prior to being sealed ontoperipheral rims 10 of trays 6, this film 4 is in one piece.

The device has a spacer plate 5 between deep-drawable film 4 and trays6. This spacer plate 5 has openings 13 that correspond with trays 6.

A supporting apparatus is assigned to supporting tables 8 in the regionof lower tool 9. This supporting apparatus is formed by the top sectionsof lower tool 9. Depressions 14 into which peripheral rims 10 of trays 6may protrude are introduced in the surface of lower tool 9 in the regionof this supporting apparatus.

FIG. 2 shows the state after lowering of supporting tables 8 via frame11. Trays 6 are placed on the supporting apparatus of lower tool 9.Their peripheral rims 10 are supported by lower tool 9.

Spacer plate. 5 is placed on the lower tool. Deep-drawable film 4 restson spacer plate 5, and upper tool 1 having sealing tools 2 and cuttingdevices 3 is moved to film 4. Cutting devices 3 are already almost onfilm 4, and they are moved along the assigned edges of spacer plate 5 ata close distance when they come closer to trays 6, as shown in FIG. 3.

FIG. 2 also shows that air is suctioned via air channels 15 out of thesurrounding region of trays 6 (arrow 161). This creates a vacuum in thesurrounding region of trays 6.

In FIG. 3, cutting devices 3 are not moved all the way to peripheralrims 10 of trays 6. The lowest position of holders 12 of cutting devices3 rests on stops 17. These stops 17 keep cutting devices 3 at a distancefrom peripheral rims 10. Therefore, these rims 10 are not cut by cuttingdevices 3 since cutting devices 3 are able to recede in a spring-likemanner into their knife holders 12. Sealing tools 2 are then used toheat-seal the cut regions of deep-drawable film 4 onto peripheral rims10. Film 4 is heated at the same time in preparation for the deep-drawoperation. In addition, air which ensures tight fitting of the heateddeep-drawable film 4 on objects 7 located in trays 6 in connection withthe vacuum prevailing in the region of trays 6 is supplied viaoverpressure lines 16 through upper tool 1 and sealing tools 2. Objects7 may be meat products, for example.

FIG. 4 shows the state of the device after ejection of trays 6. Uppertool 1 and lower tool 9 are separated and spacer plate 5 is lifted fromtrays 6. The scraps of deep-drawable film 4 remaining after cutting areremoved. After the sealing operation, trays 6 may be removed from lowertool 9 which is then able to accommodate new trays 6. In this context,the device may function in cycles, e.g. with 6 cycles per minute.

The device of the present invention may also be a sealing device viawhich trays may be sealed using films that are not deep-drawn via theskin method. The same device may therefore be used for differentpackaging types in which identical standardized basic packaging such astrays 6 are used.

Deep-drawable film 4 is cut to size, this film 4 is heat-sealed ontoperipheral rims 10, and film 4 is deep-drawn preferably in the samecycle to shorten the processing time.

Cutting devices 3 are not directed through the plane of peripheral rims10. FIG. 5 shows that deep-drawable film 4 is cut cleanly and that aregion of peripheral rim 10 free of film 4 remains in the region of thisperipheral rim 10. Cutting devices 3 do not cut peripheral rim 10 andtherefore are also not able to be damaged by sections of the objects tobe packaged protruding beyond rim 10, such as ice or bones.

Film 4 fits tightly on the walls of container 6 and on objects 7 presentin the depression of the container, as shown in FIG. 5.

1. A method for the gastight packaging of objects using a film materialfitting tightly on the objects using a vacuum, the object being placedin a tray and a deep-drawable film being attached to the tray forsealing, wherein a tray (6) having at least one peripheral rim (10) isused to form the packaging, the deep-drawable film (4) is cut to thesize of the peripheral rim (10), and the deep-drawable film (4) isapplied subsequently and/or simultaneously to the peripheral rim (10) ina gastight manner.
 2. The method as recited in claim 1, wherein thedeep-drawable film (4) is heat-sealed onto the peripheral rim (10). 3.The method as recited in claim 1, wherein a vacuum is situated in thesurrounding region of the tray (6).
 4. The method as recited in claim 1,wherein an overpressure may be formed in the surrounding region of thedeep-drawable film (4) on the side facing away from the tray (6).
 5. Adevice for the gastight packaging of objects using a film materialfitting tightly on the objects using a vacuum, preferably for carryingout the method as recited in claim 1, including a supporting surface forat least one tray and including at least one sealing tool for thedeep-drawable film, wherein the device has at least one cutting device(3) for the deep-drawable film (4).
 6. The device as recited in claim 5,wherein the cutting device (3) includes knife blades.
 7. The device asrecited in claim 5, wherein the cutting device (3) is spatially assignedto the sealing tool (2).
 8. The device as recited in claim 7, whereinthe cutting device (3) moves around sealing tool (2).
 9. The device asrecited in claim 5, wherein the supporting surface for the tray (6)and/or the sealing tool (2) is designed to be height-adjustable.
 10. Thedevice as recited in claim 9, wherein the supporting surface has atleast one supporting apparatus for the peripheral rim (10) of the tray(6).
 11. The device as recited in claim 10, wherein a spacer plate (5)which may be placed on the supporting apparatus for the peripheral rim(10) is situated between the trays (6) and the deep-drawable film (4),the peripheral rim (10) remaining at least sectionally free in thisprocess.
 12. The device as recited in claim 11, wherein at least oneopening (13) able to be moved into a covering position with a container(6) is situated in the spacer plate (5).
 13. The device as recited inclaim 12, wherein the sealing tool (2) has dimensions corresponding tothose of hole (13) in the spacer plate (5).
 14. The device as recited inclaim 13, wherein a cutting device (3) assigned to the sealing tool (2)may be moved past an edge of the hole (13) of the spacer plate (5) at aclose distance.
 15. The device as recited in claim 14, wherein thecutting tool (3) is decoupled from the sealing tool (2) and isspring-suspended.
 16. The device as recited in claim 5, wherein at leastone overpressure line (16) runs through the sealing tool (2). 17.Packaging for at least one object including a tray and a deep-drawablefilm to be placed on the tray, wherein after being placed on at leastone peripheral rim (10) of the tray (6), the deep-drawable film (4)sectionally covers this rim (10).
 18. The packaging as recited in claim17, wherein a peripheral rim (10) of the tray (6) surrounds theperiphery of at least one depression in the tray (6).